Seamless theme switching option in igniteui-react-excel and igniteui-react-spreadsheet package

[JinniaChathoth]

We have a feature requirement where we need to switch between dark and light themes. With the current implementation done in Igniteui excel package, no such functionality is available for theme switching.
We are requesting for a new feature implementation in igniteui-react-excel and igniteui-react-spreadsheet package for seamless theme switching based on the desired theme value.
It'll be helpful if a new property is introduced in the package with which we can fulfill the above mentioned requirement